Television and telephotography



Jan. 28, 193p. RTCHEQULQFF 1,745,029

TELEVI S I ON AND TELEPHOTOGRAPHY Filed Feb. 9. 1927 UNITED STATES PAENT or lcE BORIS B'IGHEOULOII', 01 LONDON, ENGLAND I TELEVISION ANDTELEPHOTOGRAPHY Application filed February 9, 1927, Serial No. 167,045,and in Russia June 27, 1922. v

5 transmission at a distance being effected over electrically conductingwires or through the intermediary of electro-magnetic waves.

One main feature of the presentinvention consists in causingaphoto-electrically sensitized point or small surface provided at thetransmitting end to vibrate in twodirect-ions at right angles to oneanother and scan a rojected image, the said vibrating photo-e ectrioallysensitized point or surface forming part of a photo-electric cell andthe variations of the photo-electric current produced as a result of thediflerent intensities of illumination of the different points of theimage being transmitted in a known manner to the receiving end.

Another main feature'of the invention consists in causing a fluorescentor luminescent point or small surface provided at the receiving end tovibrate in two directions at right angles to one another in synchronismwith the vibrations of the photo-electrically sensitized point'or smallsurface provided at the transmitting end and its fluorescenceor'luminescence to be -variedin accordance with the variations of thephoto-electric current.

The invention also broadly consists in providing the photo-electricallysensitized oint or small surface or the fluorescent or uminescentpoint,at the end of a spring arranged to vibrate in one plane, the other endof walls of a tube or casing within which the springs are mounted, whichwalls are coated with a photo-electric substance.

The invention is illustrated by way of example in the accompanyingdiagrammatic drawings, in which o- Figure 1 is a diagram of the generalarrangement according to the invention;

Figure 2 is an elevation of a modification of the positive electrodeused in the transmittin apparatus;

igure 3 is a sectional elevation through a modification of the positiveelectrode and part of the vacuum tube used in the transmittingapparatus;

Figure 4 1s a sectlonal elevation of a further modification 'of thevacuum tube used at the transmitting end and Figures 5 and 6 are twofurther diagrams illustrating modifications ofthe method of energizingthe electromagnets operating upon the springs.

In carrying the invention into efiect according to one mode, two flatsprings a and 6 connected end to end are mounted within a vacuum tube 0,preferably of rectangular cross section, and two electromagnets d and e,arranged outside the said vacuum tube cause the said two springs tovibrate in two planes at right angles to one another. The end 7 of thespring 6 is fixed in the interior of the tube 0 whilst the free end g ofthe spring a is coated with a photo-electrical substance and facesatransparent opening it of the tube. The image 7; to be transmitted isprojected preferably through a lens 3' or other suitable optical systeminto the tube and the photoelectrically sensitized free end 9 of thespring a vibrates so as to scan the image 2' projected into the tube.The photo-electrically sensitized end 9 is electrically connected to thenegative pole of the source of currentk and another electrode Z mountedwithin the tube 0 is connected to the positive pole of the source ofcurrent, the said photo-electric substance and electrode constitutingtogether a photo-electric cell.

The two electromagnets d, e, are energized by alternating or interruptedcurrents in such a manner as to cause the spring a to vibrate at asubstantially higher rate than the spring. 12, the periodicity of thetwo currents being for instance 1000 and 10 respectively.- In Figure 1,m and n are two alternating current machines supplying currents ofdifferent frequencies to the respective electromagnets d and a each ofwhich may be provided in pairs. Use may be made of a singleelectromagnet DE as shown in Figure 5 energized by currents of differentfrequencies received from the machines m and n through the transformers'm n According to a further modification, the single electromagnet has asingle pole arranged to face the spring which is intended to oscillateat the hi her frequency, its winding being energizedfiiy the twofrequencies. Accordin to a still further modification, as illustrate inFigure 6, the two electroma ets d e, are ener zed by means of tunedcircuits M and N w ich are excited in any well-known manner throu h theintermediary of transformers m and n The fluctuations of thephoto-electric current are transmitted at a distance either through theintermediary of electrically conducting wires, as indicated by theinterrupted lines 1 and 2, or by means of electro-magnetic waves,preferably after the photo-electric currents have been suitablyamplified at the transmitting end by means of an amplifier p.

At the receiving end the photo-electric currents are arranged to controlthe cathode rays or stream of electrons emitted by an incandescentcathode g or the like heated by a source of current g over a variableresistance 9 preferably in a device 0 working on the same principle as athermionic tube. The

tube comprises in addition to the incandescent cathode and grid 8, aspring arrangement similar to that referred to in connection with thetransmitting apparatus with the exception that the free end 9 of thecompound s ring a b is provided with a fluorescent or uminescent point.This spring acts as the anode. t is a reflector which is connected tothe negative pole of the high-tension battery T. Two electromagnets (1e,, (or pairs of electromagnets) are used in conjunction with thecompound spring, one of the electromagnet's controlling the vibrationsin one direction and the other electromagnet the vibrations in adirection at right angles to the direction of the vibrations controlledby the first electromagnet. These two elec tromagnet-s are electricallyconnected over the lines 3, 4 and return conductor 5, with thecorresponding electromagnets d, 0, provided at the transmitting end andare energized by the alternating or interrupted currents which flowthrough the latter electromagnets so that the two springs at thereceiving end vibrate in synchronism with the two springs at thetransmitting end.

The photo-electric currents reaching the receiving end are preferablyamplified through an amplifier 1' and finally rectified by a rectifier ubefore they reach the grid 8 which controls the stream of electronsemitted by the incandescent cathode g and bombarding the fluorescent orluminescent end 9 of the spring.

The anode I provided at the transmitting end may be of rectangular shapeas shown in Figure 1, or of disc or plate shape, in the latter casebeing made meshed in such a manner (see Figure 2) as to allow thepassage of the rays of light into the interior of the tube. It is,however, to be understood that any other form of anode may be used, suchas for instance arin of semi-circular cross-section as shown in igure 3,the front end b of the tube 0 being correspondingly shaped.

The photo-electric sensitive end 9 of the spring may be in the form of apoint or in t e form of a small surface WhlCh may be concave, as shownin Figure 4, flat or convex, and may be used with -a diaphragm vinterposed between the photo-electric surface 9 and the transparent endh of the tube 0 through which the rays of light penetrate therein, thesaid diaphragm being provided with one or more perforations such as '0of any desired size to allow the rays of light to reach thephoto-electric surface 9. The diaphragm isv convex, but of course it maybe made fiat or concave and be used in conjunction with any of the abovementioned small surfaces 9 covered with the photo-electric substance.-The diaphragm '0 may also be made of metal and constitute the secondelectrode, viz: anode of the photo-electric cell, as indicated in Figure4. Inall these combinations of photo-electric surface and diaphragm, thelatter may be arranged to be stationary or moved together with thephotoelectric point or surface, care being however taken that thediaphragm when made of metal should not make electric contact with thephoto-electric surface ,or the metallic parts which are connectedthereto. In Figure 4, 'w are insulating-members by means of which thediaphragm a is connected to and supported by the photo-electric surfaceg.

It is to be understood that any part of the tube may be coated with thephoto-electric substance including the back part thereof. It is also tobe understood that either the front or the back surface of the diaphragmabove referred to or both may be covered with a photo-electricsubstance. phragm may be so formed as to act as a reflector.

The

rings a, 6, a and b which are preferably at and arranged to lie withtheir planes at right angles to one another are secured together throughthe intermediar of a ball A, which is provided'on opposite aces with twoincisions at ri ht angles to one another to receive the said springs.The natural frequencies of the said springs both at the transmitting endand at the receiving end correspond to the two different frequencies ofthe currents flowing through the two electromagnets.

Further the dia-- I one and thesame periodicity are sent through all theelec'tromagnets but the natural frequencies of the two springs are madeto be for instance 10 and 1000 respectively.

The reproduction of the image at the receiving end may be projected ontoa screen B, such as throu h the intermediary of a magnifying lens orother optical system or be photographed.

The method of television hereinbefore described may be usedincOmbination with any known system of telephony so that the images maybe reproduced simultaneously with speech or music. a

I wish it to be understood that the details for carrying the inventioninto effect may be modified in various respects without in any waydeparting from the spirit of the invention.

What I claim is:

1. A method of electrically transmitting images, consisting inprojecting an image into the interior of a photo-electric cell,vibrating a small surface within the photoelectric cell intwo-directions at right angles to one another so as to scan the whole ofthe projected image and causing the said small surface to vary thecurrent of the photo-electric cell according to the light that fallsupon the said small surface durlng its vibrations.

2. A method of electrically transmitting ima es consisting in projectingan image into the mterior of a photo-electric cell, vibrating a smallphoto-electrically sensitized surface within the photo-electric cell intwo directions at right angles to one another so as to scan the whole ofthe pro 'ected image, whereby the said small photo-e ectricallysensitized surface causes the current of the photo-electric cell to varyaccordin to the light that falls upon it during'its vi rations.

3. An apparatus for electrically transmitting images, comprising aphoto-electric cell and a mechanically vibrating device within thephoto-electric cell, the said device being capable of vibrating in twodirections at right angles to one another and of causing the currents ofthe photo-electric cell to fluctuate according to the light that fallsupona particular small surface of the vibrating device during itsvibrations.

4. An apparatus for electrically transmitting images comprising aphoto-electric cell, a compound spring mounted within the said cell,which compound spring is constituted by two flat s rings connectedtogether in alignment wit one another but so that their planes shall beat right angllzs to one another,

one end of the one sprin ing fixed within the tube and the free en ofthe other spring being capable of scannin the whole of the image and ofvarying t e current of the photo-electric cell accordin to the lightthat falls upon it, and means or vibrating the com ound spring in twodirections at ri ht ang es to one another in such a manner t at thefrequency of the vibrations in one direction shall be substantiallygreater than the frequency of the vibrations in the other direction.

5. An apparatus as claimed in claim 4, in which the free end of thecompound spring is photo-electrical1y sensitized.

6. An apparatus for electrically transmitting images as claimed in claim4, and having a perforated diaphragm. in front of the free end of thecompound spring and means for supporting the said diaphragm on the freeend of the compound spring.

7. An apparatus for electrically transmitting images as claimed in claim4, and having a perforated diaphra m in front of the free end of thecompoun spring, a coatin of photo-electric substance on the free en ofthe compound s ring, and means for supporting the diap ragm on the saidfree end of the compound spring.

8. 'An apparatus for electrically transmitting images, as claimed inclaim 4, and having a perforateddiaphra m in front of the free end ofthe compoun spring, a coatin of photo-electric substance on the free end0 the compound spring, and means for sup-v porting the perforateddiaphragm on the saidfree end of the compound spring, the saidperforated diaphragm being made of metal and serving as the anode of thephotoelectric cell.

In testimony whereof I have signed my name to this s igcification.

I OBIS RTCHEOULOFF.

